1. Field of the Invention
The invention relates to a clutch disk with a torsional vibration damper, with an idling system and a load system. A hub disk is mounted with play on a hub via a toothing and cover plates are arranged at both sides coaxially thereto. A friction arrangement is provided which can be activated in the idling state after a partial rotation of the cover plate and hub disk via a pre-damper having springs.
2. Description of the Prior Art
A clutch disk of this kind is known, for example, from German reference DE 40 26 765. This clutch disk is outfitted with an idling system which has a two-stage friction construction in order to optimize the adapting or adjusting possibilities of the idling system.
During cold operation, the torsional vibration damping characteristics, although fundamentally more favorable, must, however, already transmit a considerable idling torque. Therefore, another spring stage is brought into play via the two-stage friction arrangement concurrently with the higher frictional force. In this way, even motor vehicle drives having a quite sensitive response can be favorably adapted. At the same time, the springs of the predamper also provide for an exact return of the friction arrangement when movement is reversed.
The springs of the additional spring stage are arranged in circumferentially enlarged windows of the hub disk. The friction arrangements are formed by a friction segment adjoining the front end of each of the windows. This friction segment fills the axial space between the two cover plates and is acted upon axially by the springs of the load friction device. This offers the advantage that no additional springs are necessary for the additional friction stage and the friction segment can be outfitted with a sufficient friction volume. However, this friction arrangement causes a so-called dragging or delayed friction. Furthermore, a clutch disk of this kind requires a corresponding quantity of friction elements resulting in a correspondingly high cost for storage and assembly.